7 Changes To Make If You Want To Lose 20 Pounds Or More

"Substantial weight loss is not a sprint. It's not even a marathon. It's the rest of your life," says Janet Hamilton, CSCS, an exercise physiologist with Running Strong in Atlanta. "It is your new normal."

When you're trying to lose a sizeable amount of weight, it's extra critical to find a weight loss approach that you can envision yourself using, well, forever. After all, a meta-analysis published in the Journal of the American Medical Association concluded that the best diet is one that you can stick with over the long term.

Adopting a "new normal" always feels a bit challenging at first. But it shouldn't include deprivation, ditching social events, or blacklisting entire food groups.

"I always look at trying to lose a large amount of weight like making a sculpture," says Albert Matheny, RD, CSCS, a registered dietitian and trainer with SoHo Strength Lab in New York City.  When you sculpt something, you have to build a base before you get into details, he says.

Translation: Start with general changes, like integrating more veggies into your meals and eating breakfast every day, as opposed to the nitpicky stuff like switching up the creamer in your coffee. You can work on the finer points after you get the big stuff down pat. (Check out these fat-burning moves from Women's Health's Look Better Naked DVD.)

The 1 to 2 pounds of weight loss per week rule applies whether you have 5 or 50 pounds to lose, says Matheny. (FYI: Cutting 500 calories a day by eating healthier and exercising will get the job done.)

But if you're trying to drop a substantial amount, that timeline can seriously delay your goal-weight gratification. 

Instead of getting hung up on the scale, zone in on other payoffs associated with your new and improved lifestyle. Maybe it's sleeping better, having more energy, or being able to run a mile, says Baltimore-based trainer Erica Suter, CSCS. These are all signs that you're making huge progress and getting healthier—which is the point of losing weight in the first place.

The silver lining of having a lot to lose is that you can achieve a healthy calorie deficit with relatively small changes to your overall eating habits and exercise routine.

Don't underestimate the benefits of taking your conference calls standing, parking farther from the supermarket's entrance, or having a refillable water bottle on you at all times. Sure, it's not the same as a solid sweat session or eating salads every day, but little things can boost your calorie burn.

To lose weight, you need to eat fewer calories than you burn per day. But as you drop pounds, your body doesn't need as many calories to subsist as it did before.

Here's why: Calories are energy. And the smaller your body is, the less energy you burn through each day. Plus, through the process of slimming down, you'll probably lose some muscle, the furnace fueling your metabolism. Finally, the more weight you lose, the harder your body works to hold on to every calorie you consume, a phenomenon known as starvation mode, says Hamilton.

"Basically, you require fewer calories to maintain your new weight than someone of the same weight who was never overweight," she says. This last sucky side effect frequently happens to people who lose 10% or more of their body weight.

For that reason, staggering the amount of calories you cut as you lose weight can help your body adjust to its new energy intake. Try cutting 500 calories from your daily food intake when you first start out. If, after a month or two, you start plateauing for 2 weeks or more, you might need to cut another 100 calories, says Matheny. Still, it's important to make sure you never get below 1,200 calories per day.

We beat this drum a lot around here because, hey, strong is the new sexy. And when it comes to weight loss, more strength training = more fat loss. Like we said, as you lose weight, your basal metabolic rate (the number of calories you burn just breathing) drops, along with your lean muscle mass.

Strength training is your best bet to combat both issues, says Suter. Aim to hit the weight room 3 to 5 days per week, depending on your resistance-training experience and how hard you work out during each session.